June Stevens, Jill E. McClain and Kimberly P. Truesdale University of North Carolina at Chapel Hill

The Atherosclerosis Risk in Communities (ARIC) Study was a prospective study funded by the National Heart Lung and Blood Institute (NHLBI), which examined the etiology and natural history of atherosclerosis and clinical atherosclerotic disease in four US Communities1. Population-based samples were recruited in Forsyth County, NC; Jackson, MS; northwestern suburbs of Minneapolis, MN; and Washington County, MD. Details on the sampling, recruitment and clinic examination have been reported1 2. At baseline (1987 - 1989) the cohort included 6,050 white women, 5,428 white men, 2,635 African American women and 1,631 African American men, for a total of 15,744 participants. Participants were examined on four occasions at 3-year intervals. At the final visit, 73.6% of the cohort was re-examined and 9.2% of the cohort was deceased.

The ARIC study protocol included assessments of weight gain, obesity, diet and physical activity. Body weight and waist and hip circumferences were measured at all four examinations and height was measured at visits 1, 3 and 4. Self-reported body weight at age 25 was obtained at baseline. Subscapular and triceps skinfolds were measured at visits 1 and 2. Information on usual dietary intake over the preceding year was obtained at visits 1 and 3 using an interviewer-administered 66-item modified Willett semi-quantitative food frequency questionnaire3. Physical activity over the past year was assessed at visits 1 and 3 using an interviewer-administered, modified4 Baecke questionnaire5, which yielded 3 semi-continuous scores from 1 to 5 for sport, leisure and work.

Only a limited number of studies have used data from ARIC to examine predictors of weight gain, obesity, diet or physical activity.

Four studies have examined predictors of BMI or weight gain:

Self-reported dieting was associated with a larger mean annual weight gain than non-dieting in white men and women and in African American women6.

Aging was associated with increases in BMI into the 8th decade of life. Later birth cohorts tended to have higher BMI levels and generally showed stronger association between aging and BMI7.

Higher fasting insulin concentration was associated with a lower rate of weight gain in ARIC (though not in CARDIA)9.

Three studies have examined predictors of dietary patterns:

Higher education level was associated with lower per-energy intakes of meats, eggs, chicken with skin, and whole milk and with higher intakes of fruits, vegetables, fish, chicken without skin and low-fat milk10.

African Americans with one or more large chain supermarkets in the census tract where they lived had increased likelihood of meeting dietary guidelines for fruit and vegetable intake compared to those with no supermarkets. This association was not statistically significant among whites. In addition, there were no significant associations between dietary patterns and number of grocery stores, or full service or fast food restaurants11.

Living in lower income neighborhoods was associated with decreased energy-adjusted intake of fruites, vegetables, and fish and increased intake of meat. After adjusting for individual-level income, patterns were similar, though most associations were no longer statistically significant10 12.

One study examined predictors of physical activity and inactivity:

Retirement was associated with an increase in sport and exercise participation and with an increase in television watching13.

Several proposals have been approved by the ARIC Steering Committee for work that is currently in progress:

Gender, BMI at baseline and at age 25, smoking and smoking cessation, pre-existing illness, education, physical activity, energy intake, several foods and nutrients, anti-depressants, diabetes and television as predictors of weight gain.

Television as a predictor of physical activity and diet.

Further work is on-going to characterize the environments in which ARIC participants lived, and more investigations of the influence of these factors on obesity-related outcomes are planned.